The invention relates to a method for operating a test bench to carry out simulation drives of a vehicle placed on the test bench. The invention further relates to a test bench configured, e.g., to carry out this method.
Test benches for driving simulation are known in the art in several variants (e.g. roller test benches, conveyor belts). Roller test benches are configured as a counterpart to a tire, and are fashioned as one or as a plurality of rotatable rollers or cylinders (single rollers, double rollers). These rollers receive the tire and follow a motion imparted to the tire or produce such a motion. Likewise, conveyor belts or running, closed belts stretched across two or more rotatable cylinders are configured as a counterpart to a tire. These belts receive the tire and follow an imparted motion or produce a motion. As used in the present application, the term ‘roller’ and the like encompass rollers, cylinders, belts, etc.
In a first drive modus, in particular, a plurality of drives are mechanically intercoupled with belts using rollers. During acceleration or deceleration, the individual drives are mechanically interlinked via couplings. If the system is accelerated by means of a vehicle, the speed change depends on the magnitude of the forces on the surface of the wheels and on the mechanically installed mass or the moments of inertia of all the mechanical parts that are to be set in motion.
In another drive modus, a unit (i.e., a drive train that can receive a wheel) is driven by an electric motor. If there are several respective units, there is no mechanical link between the units, except in service operating modes. One unit or two units (1 axle) is/are designated as the master. It is possible to control the master drive to a constant torque (positive or negative for load relief or loading), but the drive is not speed-controlled. The actual speed of the master drive is measured and provided as a setpoint value to the slave drives, if any. Under these conditions, it is possible that the rpm's and the speeds of the four sets of rollers differ from one another, because there is no mechanical link between the individual rollers and drives.